Asp.Net防止恶意刷新网页
页面刷新控制器
using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI;
namespace CSFramework.BLL
{
/// <summary>
/// 页面刷新控制器.
/// Session[Tag]="[FirstRefreshTime];[RefreshCounts];"
/// 比如: "2008-01-01 14:23:00;2" 说明:2008-01-01 14:23:00访问网页,且刷新了2次
/// "2008-01-01 14:23:00;5;Y" 说明:2008-01-01 14:23:00访问网页,且刷新了5次.当标记为"Y",60秒后才能刷新网页。
/// </summary>
public class PageRefreshCounter
{
private int _delaySeconds = 30;//预设60秒后刷新网页
private int _refreshBetween = 15;//在设定时间内刷新超出多少次.
private int _refreshCountMax = 5;//在设定时间内刷新不超出指定次数.
private static PageRefreshCounter _Instance = null;
public static PageRefreshCounter Instance
{
get
{
if (_Instance == null)
{
int delaySeconds = 60;
int refreshBetween = 3;
int refreshCountMax = 4;
_Instance = new PageRefreshCounter(delaySeconds, refreshBetween, refreshCountMax);
}
return _Instance;
}
}
public void SetLock(Page curPage, bool isLock)
{
string mark = isLock ? "Y" : "N";
string sid = GetRefreshSessionID(curPage);
string tag = ConvertEx.ToString(curPage.Session[sid]);
string[] sps = tag.Split(new char[] { char.Parse(";") });
curPage.Session[sid] = sps[0] + ";" + sps[1] + ";" + mark;
}
//是否恶意刷新.10秒内刷新>3次视为恶意刷新.
public bool IsDangerousRefresh(Page curPage)
{
string tag = ConvertEx.ToString(curPage.Session[GetRefreshSessionID(curPage)]);
string[] sps = tag.Split(new char[] { char.Parse(";") });
DateTime loadtime = DateTime.Parse(sps[0].ToString());
TimeSpan span = DateTime.Now - loadtime; //最后一次时间与当前时间对比
//网页被标记为恶意刷新
if (sps.Length == 3 && sps[2] == "Y")
{
if (span.TotalSeconds > _delaySeconds)
return false;
else
return true;
}
int counter = int.Parse(sps[1]);
bool isDangerousRefresh = ((span.TotalSeconds <= _refreshBetween) && (counter >= _refreshCountMax));
return isDangerousRefresh;
}
//构造器.传入当前网页对象及延时秒数
public PageRefreshCounter(int delaySeconds, int refreshBetween, int refreshCountMax)
{
_delaySeconds = delaySeconds;
_refreshBetween = refreshBetween;
_refreshCountMax = refreshCountMax;
}
//当访问者恶新页面而暂时中断访问页面.当系统时间超出延时时间,打开页面访问权限.
public void UpdateDelayCounter(Page curPage)
{
string tag = ConvertEx.ToString(curPage.Session[GetRefreshSessionID(curPage)]);
if (tag == string.Empty)
{
ResetCount(curPage, DateTime.Now, 1);
return;
}
string[] sps = tag.Split(new char[] { char.Parse(";") });
DateTime loadtime = DateTime.Parse(sps[0].ToString());
TimeSpan span = DateTime.Now - loadtime;
if (sps.Length == 3 && sps[2] == "Y")
{
if (span.TotalSeconds > _delaySeconds)//超出60s延时,重设
this.ResetCount(curPage, DateTime.Now, 1);
else
return;
}
if (span.TotalSeconds > _refreshBetween) //计数器超界，重设
ResetCount(curPage, DateTime.Now, 1);
else
AddCounter(curPage);
}
//获取页面刷新控制器在Session内的标识ID
private string GetRefreshSessionID(Page curPage)
{
return "RFC_" + curPage.GetType().Name;//Refresh Counter
}
//增加刷新记数器
private void AddCounter(Page curPage)
{
string id = GetRefreshSessionID(curPage);
string tag = ConvertEx.ToString(curPage.Session[id]);
if (tag == null)
ResetCount(curPage, DateTime.Now, 1);
else
{
string[] sps = tag.Split(new char[] { char.Parse(";") });
int add = ConvertEx.ToInt(int.Parse(sps[1])) + 1;
tag = sps[0] + ";" + add.ToString();
curPage.Session[id] = tag;
}
}
//重设计数器
private void ResetCount(Page curPage, DateTime refreshTime, int count)
{
string tag = refreshTime.ToString("yyyy-MM-dd HH:mm:ss") + ";" + count.ToString();
curPage.Session[GetRefreshSessionID(curPage)] = tag;
}
}
}
设计一个页面基类：
using System;
using System.Collections.Generic;
using System.Text;
namespace CSFramework.BLL
{
/// <summary>
/// 刷新页面计数器.
/// </summary>
public class PageBaseRefreshCounter : PageBase
{
/// <summary>
/// 当统计数大于限制的次数，是否要跳到消息页
/// </summary>
protected bool _FireShowMessage = true;
protected override void OnPreLoad(EventArgs e)
{
if (!IsPostBack)
{
bool restrictRefresh = true;
if (restrictRefresh == true)
{
PageRefreshCounter.Instance.UpdateDelayCounter(this);
if (PageRefreshCounter.Instance.IsDangerousRefresh(this))
{
PageRefreshCounter.Instance.SetLock(this, true); //锁定网页不可刷新.指定多少秒后才能刷新.
if (_FireShowMessage) PageMessage.ShowMessage(this, PageMessage.DANGEROUS_REFRESH);
}
}
}
base.OnPreLoad(e);
}
}
}
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